Manure and Compost Suppliers
In the past, the inadvertent use of manure containing aminopyralid has led to a small number of incidents involving alleged damage to sensitive crops being reported on allotments and in gardens in the UK.
The manure possibly came from farm animals or horses that had eaten pasture or conserved forage from grassland treated with a herbicide which contains a small amount of aminopyralid.
Here are some facts about aminopyralid for anyone selling manure and compost products to landscape contractors, gardeners and allotment holders.
What is aminopyralid?
Aminopyralid is the active ingredient in herbicides such as Forefront, Pharaoh, and Banish. These herbicides are among the most effective for controlling and eliminating many deep-rooted perennial weeds found in grassland, including docks, thistles, nettles, and ragwort.
Ragwort control is especially important, as it can be deadly if eaten by horses.
When grassland is sprayed with aminopyralid, it kills target weeds but does not affect the grass. However, when this grass is eaten by animals, either out in the field or as conserved feed such as hay, haylage or silage, a small amount passes out with the resulting manure.
Can we accept manure from treated paddocks?
Twelve months after application of aminopyralid the grassland can be considered aminopyralid-free and grass can be used for grazing or conservation with no restrictions.
Manure with suspected aminopyralid residue can only be used on grassland grazed by cattle or sheep.
The aminopyralid residue in manure will not start to break down in manure heaps, until such time as the manure is applied to grassland or incorporated into soil. The areas to which this manure is applied cannot be considered aminopyralid-free until the following year.
DO NOT, under any circumstance, supply this manure to 3rd parties and in particular not to gardeners or allotment holders.
How can we tell if there is any aminopyralid in the manure?
Dow AgroSciences has developed a test to check whether manure or compost contains residues of aminopyralid. (See "What can I do" in the panel on the right.)
Manure samples can also be sent for laboratory analysis.
If you are selling manure that is known to contain aminopyralid you must inform your customers, and warn them not to apply it to ground in which sensitive crops will subsequently be grown.
Does aminopyralid break down in rotting manure?
Not if the manure is stacked.
However, micro-organisms in well-aerated soil will break aminopyralid down over a period of time. If the manure is incorporated into the soil and turned over frequently, the chance of any adverse effects on sensitive crops grown in that soil diminishes significantly after six months.
Where can I get more information?
Link to the following sites for more information about the use and effects of aminopyralid:
Chemicals Regulation Directorate:
http://www.pesticides.gov.uk/garden.asp?id=2480
Department for Environment, Food, and Rural Affairs:
